HRW has a large archive spanning from 1952-2003 at Columbia University. You can reach them here: Phone: 212-854-8046 Email: [email protected] and they have a multi-media archive based in New York, but I was unable to find a librarian or archivist to contact. My suggestion would be to use their mail form to contact them Sorry to not have an exact solution for you.

They also do have a Toronto office, where it might be easier to get information on what you are looking for, since it's local for you.